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Some preliminary tests on VGT data over France J-L CHAMPEAUX, L FRANCHISTEGUY, S. GARRIGUES

Some preliminary tests on VGT data over France J-L CHAMPEAUX, L FRANCHISTEGUY, S. GARRIGUES CNRM/GMME/MATIS. Cloud mask evaluation. Comparison between:. Status map cloud mask. New VITO cloud mask (Lissens and al, Belgirate 2000) with thresholds tuned over the world applied

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Some preliminary tests on VGT data over France J-L CHAMPEAUX, L FRANCHISTEGUY, S. GARRIGUES

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  1. Some preliminary tests on VGT data over France J-L CHAMPEAUX, L FRANCHISTEGUY, S. GARRIGUES CNRM/GMME/MATIS

  2. Cloud mask evaluation Comparison between: • Status map cloud mask. • New VITO cloud mask (Lissens and al, Belgirate 2000) with thresholds tuned over the world applied to TOA reflectance: a pixel is declared clear if B0<493 OR SWIR<180. • New tuned cloud mask with thresholds tuned over France for surface reflectance (S1 data): a pixel is declared cloudy if B0>=220 AND SWIR>=180

  3. What strategy for the cloud mask? • use the status map • (poor quality) • use the VITO thresholds • Must be applied to TOA reflectances • determine new thresholds on B0 • for specific window

  4. Work on bidirectional effects: • Evaluation of bidirectional effects • in different solar-target-sensor • configurations over homogeneous • landcover areas • Implementation and test • of BDC method • (B.Duchemin, CESBIO) • Proposal VEGA2000: • Determination of global albedo • from VGT products

  5. VEGA2000 proposal : Determination of global albedo products from VGT instrument data for use in numerical weather forecast and climate models.L. FRANCHISTEGUY(CNRM/GMME) Preliminary study with a data set of VGT-P products (April 1998 – March 1999)a)      Atmospheric corrections : SMACTOA reflectances  surface reflectancesb)      BRDF kernel-driven model inversion : correction of bidirectional effects (30 days compositing period with a sliding periodof 10 days).c) Retrieval of land surface albedo (directional albedo) for a 100*100 km domain located insoutheast part of France.

  6. Method for retrieval of surface properties • Inversion of a BRDF model : s, v,  = k0 + k1  f1s, v,  + k2  f2s, v,  • (model of Roujean et al., 1992) • K0: Normalized reflectance for s=0 and v=0

  7. DECIDUOUS PIXELS ( South of France) AA

  8. Unsupervised classification using 10 days MVC ( from 1/1/2000 to 31/09/2000 over SO France Corine Land Cover dataset at 1km resolution

  9. Unsupervised classification using 10 days MVC from 1/1/2000 to 31/09/2000 over SO France

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